Intraoperative confocal laser endomicroscopy: prospective in vivo feasibility study of a clinical-grade system for brain tumors
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Published on: January 10, 2013
Irakliy Abramov1,2, Marian T Park1, Evgenii Belykh3
11The Loyal and Edith Davis Neurosurgical Research Laboratory, Department of Neurosurgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix.
Objective:
The authors evaluated the feasibility of using the first clinical-grade confocal laser endomicroscopy (CLE) system using fluorescein sodium for intraoperative in vivo imaging of brain tumors.
Methods:
A CLE system cleared by the FDA was used in 30 prospectively enrolled patients with 31 brain tumors (13 gliomas, 5 meningiomas, 6 other primary tumors, 3 metastases, and 4 reactive brain tissue). A neuropathologist classified CLE images as interpretable or noninterpretable. Images were compared with corresponding frozen and permanent histology sections, with image correlation to biopsy location using neuronavigation. The specificities and sensitivities of CLE images and frozen sections were calculated using permanent histological sections as the standard for comparison. A recently developed surgical telepathology software platform was used in 11 cases to provide real-time intraoperative consultation with a neuropathologist.
Results:
Overall, 10,713 CLE images from 335 regions of interest were acquired. The mean duration of the use of the CLE system was 7 minutes (range 3-18 minutes). Interpretable CLE images were obtained in all cases. The first interpretable image was acquired within a mean of 6 (SD 10) images and within the first 5 (SD 13) seconds of imaging; 4896 images (46%) were interpretable. Interpretable image acquisition was positively correlated with study progression, number of cases per surgeon, cumulative length of CLE time, and CLE time per case (p ≤ 0.01). The diagnostic accuracy, sensitivity, and specificity of CLE compared with frozen sections were 94%, 94%, and 100%, respectively, and the diagnostic accuracy, sensitivity, and specificity of CLE compared with permanent histological sections were 92%, 90%, and 94%, respectively. No difference was observed between lesion types for the time to first interpretable image (p = 0.35). Deeply located lesions were associated with a higher percentage of interpretable images than superficial lesions (p = 0.02). The study met the primary end points, confirming the safety and feasibility and acquisition of noninvasive digital biopsies in all cases. The study met the secondary end points for the duration of CLE use necessary to obtain interpretable images. A neuropathologist could interpret the CLE images in 29 (97%) of 30 cases.
Conclusions:
The clinical-grade CLE system allows in vivo, intraoperative, high-resolution cellular visualization of tissue microstructure and identification of lesional tissue patterns in real time, without the need for tissue preparation.
Insights
Confocal laser endomicroscopy (CLE) provides real-time, in vivo imaging of brain tumors, proving safe and feasible for intraoperative diagnosis. This technology enables noninvasive digital biopsies with high accuracy, aiding surgical decisions.
Area of Science:
- Neurosurgery
- Medical Imaging
- Oncology
Background:
- Intraoperative assessment of brain tumors is crucial for accurate diagnosis and treatment.
- Current methods like frozen sections have limitations in real-time cellular detail.
Purpose of the Study:
- To evaluate the feasibility and diagnostic accuracy of a clinical-grade confocal laser endomicroscopy (CLE) system for intraoperative brain tumor imaging.
- To assess the utility of CLE for real-time, in vivo cellular visualization and noninvasive digital biopsies.
Main Methods:
- A Food and Drug Administration-cleared CLE system was used in 30 patients with 31 brain tumors.
- Images were classified by a neuropathologist and compared with frozen and permanent histology.
- Neuronavigation was used for image-biopsy correlation, and telepathology software facilitated real-time consultation.
Main Results:
- Interpretable CLE images were acquired in all cases, with a mean acquisition time of 7 minutes.
- Diagnostic accuracy, sensitivity, and specificity of CLE compared to permanent histology were 92%, 90%, and 94%, respectively.
- The system demonstrated safety and feasibility, successfully obtaining noninvasive digital biopsies in all procedures.
Conclusions:
- Clinical-grade CLE enables real-time, in vivo, high-resolution visualization of brain tumor microstructure.
- It allows for immediate identification of lesional tissue patterns without the need for tissue preparation.
- CLE is a safe and feasible tool for intraoperative brain tumor assessment, enhancing diagnostic capabilities.
